Annual report pursuant to Section 13 and 15(d)

Noncontrolling Interests (Details)

Noncontrolling Interests (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2011
Operating Partnership
Dec. 31, 2011
Operating Partnership
Series I Preferred Units
Dec. 31, 2011
Certain consolidated entities
Noncontrolling Interests          
Percentage of overall ownership interest, some of which is not owned by entity     100.00%    
Percentage of overall ownership interest in certain consolidated entities, some of which is not owned by the entity         100.00%
Preferred units issued to an unrelated party       352,000  
Aggregate liquidation preference $ 8,800 $ 8,800   $ 8,800  
Liquidation preference (in dollars per unit)       25.00  
Priority annual cumulative return as a percentage of liquidation preference through September 22, 2019       7.50%  
Period frequency following September 22, 2019 after which there will be increases in annual cumulative preferred return (in years)       5  
Common units issuable upon conversion of each convertible preferred unit (in units)       0.5